Rotating hearth furnace



2 Sheets-Sheet -2 G. s; MCLAY ROTATING HEARTH FURNACE Filed sept. 25, 1935 March 23, 1937.

Patented Mar. 23, i931 e e y 2,074,662

UNITED STATES PATENT oFFicE j Ro'rA'rrNG HEARTH FURNACE Gavin Smellie McLay, London, England, assignor to `Wellman Seaver Rolling Mill Company, Limited, London, England, a company of Great Britain X Application September 25, 1935, Serial No. 42,104

e .In Great Britain October 12, 1934 13 Claims. (Cl. 263-7) This invention relates to` rotatory hearth furrig. 3 is a similar section on the line C-D of neces and has for one object to provide a simple, Fig. 1, and A n e I. accessible and adjustable construction of furnace Fig. 4 is a section showing a modification to a which is suitable forwithstanding relatively high still larger scale.

5 temperattures and which minimizes difficulties of Referring to Figs.` 1, 2 and 3 the outer circular 5 wall and hearth support, drooping of the walls, wall of the furnace is built up of `brickwork I creeping of the hearth, and sealing, particularly carried by a ring `'structure bolted or otherwise in the oase of large furnaces. Other objects will secured to a number of stanchions 2 arranged in become apparent from the description which fola circle. The ring structure is in two parts, the

lows. upper part 3 being bolted to the stanchions 2 and 10 The invention provides a rotary hearth furnace the lower part 4, which constitutes the lower supcomprising a roof a side wall supported sepport for the brickwork, is bolted .to the upper part arately from the roof, a hearth supported sep- 3. A layer of insulation 5 is provided behind the arately from the side wall and means for effecting brickwork I. The lower part 4 ofthe ring struca relative adjustment as to height between the ture is hollow as shown at 6 andserves for the 15 lower edge of the side wall and the adjacent or passage for cooling water. The construction of subjacent edge of the rotary hearth without movf the inner `circular wall of the furnace is exactly ing the roof. The invention also provides a similar in that thewall is carried by a ring strucrotary hearth furnace comprising means for efture boltedkor otherwise secured to a number of 2o fecting a relative adjustment as to height between stanchions arranged in a circle.V The stanchions thelower edge of a side wall of the furnace and bear the reference 2', the upper part of the ring the adjacent or subjacent edge of the rotary structure bears the reference 3', the lower part hearth without moving the roof `of the furnace 4', the layer of insulation 5', the passage for and the main body of the hearth. Such relative cooling water 6', and the brickwork l'.

adjustment may be provided for by making the Any known and usual method of keying the 25 part carrying the lower edge of the wall vertically brickwcrk and I in position may be employed. adjustable and/or by making the adjacent edge- The two sets of stanchions 2 and 2' are conpart of the rotary hearth vertically adjustable. nected by horizontal radial girders `1 and from AThus an outer and/or inner circular wall or these horizontal and radial girders the roof 8 is walls may be carried on a ring structure which supported in two cast iron ring brackets 9 and IIJ 30 is adjustable as to height upon a supporting bolted to said girders 8. II is a layer of insulastructure. Preferably, the outerand/or inner tion on the top of the roof. The furnace is fired wall or walls is or are built up of brickworlr and through both the inner and outer walls. I2 being the ring structure is in two parts of which the the burners which are preferably directed, as

3'5 upper part is bolted or otherwise secured to a shown, opposite to the motion of the hearth (in- 35 supporting structure, for example stanchions ardicated by arrows in Fig. 1). In some circum- I ranged `in a circle, andtlrre lower part constitutes stances they might be directed either normal the lower support for the brickwork and 4is se. or with the motion of the hearth. cured to the upper part. The lower parts 4, 4' of the ring structures of 0 The inner face or faces of the side wall or walls both the outer and inner walls carry depending 40 e may project over the edge or edges of the hearth circular plates I3, I3' respectively which extend disposed at substantially the bottom of the said into sandseals 44, 44'. I

wall or walls. Advantageously, the hearth is The side walls of the furnace may be arranged built up of concentric rings and consists of rings to be adjustable in height by passing the securing of refractory material carried upon rings of metal bolts, for the ring structures through slots in 45 plates. The outer and/or inner rings may be the stanchions 2,2. Or other means maybeemadjustable in height in relation to the main body ployed for adjusting the height of the side walls. of the hearth. The two side walls and the roof form a circular.

One form of rotatory hearth furnace according tunnel.

to the present invention will now be described by The hearth of the furnace is `supported on a 50 way of example and with reference to the accomnumber of concentric rings I4', |42, |43, |44, |45, panying drawings wherein:-` built up of horizontal plates. The hearth is Fig. 1 is a sectional plan, built up of a central ring portion I1, outer ring Fig. 2 is a section on the line A- B of Fig. 1, to portions I8, I9, and inner ring portions I8', I9' a larger scale, Y l

respectively. The sides of the outer plates I4'. 55

|45, extend upwards along the sides of the hearth as shown at I5, I6 respectively.

The walls I5, I6 carry horizontal flanges 20, 20' to which are bolted rings carrying downwardly depending plates 2I, 2I respectively. These plates extend into the sand seals 44, 44'.

The width of the hearth is such that its edges extend under, and preferably to the outsides of the outer and inner circular furnace walls and so that spaces 22, 22 exist between the bottoms of the furnace walls and the surface of the hearth thereunder. It will be understood that the hearth need not extend to the outsides of the furnace walls as is illustrated, but in some l5 cases may extend a little beyond the inner faces of said walls. Ihe plates I4'I |42, |43, |44, and I4 on which the hearth is carried are supported on a structure consisting of a number of radial I-beams 23 carried on two parallel circular I- beams 24, 25 braced together at intervals by radial members 28. The I-beams 24, 25 carry circular rails 2l, 28 respectively which are supported on rollers 29, 30. The face of said rollers is inclined inwardsA towards the centre of the 25 furnace structure as indicated and their outer sides have flanges II. 3|'. A rack 32 is mounted on the underside of the structure from which it is driven by toothed driving gear in known manner. 'Ihe rack I2 may be driven at one'or more points.

Projections Il. 3l' are carried on certain of the radial I-beams 23 to be positioned between projections 34. l5 and 34', I5' on the underside of the supporting plates I4', I4s respectively. 'Ihe projections 33, 33 are of a size to permit a lim- 35 ited degree of freedom of the carrier for the hearth to expand or change its shape under heat conditions. 'I'he troughs for the sand seals are bolted to the radial I-beams 23.

A usual charging opening 31 closed by a door 40 and a discharging opening 38 closed by a door are provided. 'I'he flue connection may be through the roof or through a side wall and is positioned between the charging and discharging openings. Preferably depending curtain walls Il are arranged between these two openings to prevent the heating gas passing directly to the flue from burners near to the discharge opening. Other doors may be provided in the outer and inner walls for inspection or other purposes.

40 is such a door in the inner wall opposite the discharge opening. 4| is a plate at the discharge opening to prevent damage should articles be dropped during removal from the furnace. 42 is a further curtain wall to keep the hot gases from the discharge opening.

The furnace is particularly intended for billets but it may be employed for other purposes. During operation it may be rotated continuously or may be stopped as each billet or number of billets is charged to it. Any convenient form of charging gear may be employed. The upwardly extending Walls I I, I 6 of the hearth prevent spread of the hearth due to high temperatures.

Any drooping of the side walls which may occur may be taken up by raising the ring structure on the stanchions 2. there being a small space at the top when the furnace is cold.

In the modification of the invention illustrated in Fig. 4 the `furnace hearth is built up of a number of concentric rings each supported on a separate circular ring carrier. The carrier I4 for the outer ring I 9 is bolted to the adjacent carrier I 4l and the carrier for (not shown) is similarly bolted The outer and/or inner ring may thus carrier.

be adjusted in height so as to compensate for any drooping in the outer and/or inner furnace walls due to the heat conditions.

In the furnace described above the outer and inner sides o'i' the hearth are removed from the heat of the furnace and consequently are maintained cool and they may be easily inspected and are accessible for repairs.

What I claim is:

1. A rotary hearth furnace, comprising a ilxedly supported roof, a side-wall supported separately from the roof, a hearth supported separately from the side-wall with an edge adjacent to the lower edge of the said wall, and means for effecting a relative adjustment as to height between the said lower edge of the side-wall and the said adjacent edge of the hearth without bodily adjustment of the roof or hearth.

2. A rotary hearth furnace. comprising a fixedly mounted roof, a rotary hearth of which the main body is vertically inadjustable, a side-wall having its lower edge adjacent to an edge of the said hearth, and means for eecting a relative vertical adjustment between the said lower edge of the wall and the adjacent edge of the hearth.

3. A rotary hearth furnace, comprising a supporting structure, a side-wall and adjustable securing means whereby the said wall can be adjusted as to height and secured to the said structure.

4. A rotary hearth furnace, comprising a circular `furnace-wall, a metal ring-structure carrying the said wall, a supporting structure and adjustable securing means whereby the said ringstructure can be adjusted as to height and secured to the supporting structure.

5. A rotary hearth furnace, comprising a brickwork furnace-wall, a supporting structure, a metal ring-structure in two parts, adjustable attachment means whereby the upper part of the said ring-structure is secured to the supporting structure in a vertically adjustable manner, and means for securing the lower part of the said ring-structure to the upper part thereof, the said lower part being arranged to carry the furnace wall.

6. A rotary hearth furnace, comprising a ringshaped hearth the surface-body of which is built up of several concentric rings of refractory material.

7., A rotary hearth furnace whereof the hearth comprises a series of concentric rings of refractory material and means for adjusting a marginal ring oi' the said series in height relatively to the rest of the hearth.

8. A rotary hearth furnace, comprising a side- Wall and a rotary said side-wall and having its surface composed of more than one ring of refractory material, the part of the hearth projecting under the side wall consisting of one such ring.

ring of metal plates, structure upon which carried.

10. A rotary hearth furnace,whereof the hearth comprises more than one ring-shaped section forming its surface, a relatively rigid rotary structure upon which the said sections are freely carried and positive driving elements acting between the said structure and the said sections, the said driving elementsbeing arranged to permit a deand a common supporting the said plates are freely ing vertically a marginal section of the hearth,

a circular sealing trough carried by said hearth, and depending plates respectively attached to the side wall and marginal section and arranged to dip into said trough.

13. A rotary hearth furnace, comprising a furnace-wall, means for adjusting said Wall vertically, a furnace hearth, a circular sealing trough carried by said hearth, and depending plates respectively attached to the bottom of said wall and the adjacent margin ot the hearth and ar- 10 ranged to dip into said trough.

GAVIN Smil-IE McLAY. 

